/*
 * Copyright (c) 2013 Genome Research Ltd.
 * Author(s): James Bonfield, Rob Davies
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * 
 *    1. Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 * 
 *    2. Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials provided
 *       with the distribution.
 * 
 *    3. Neither the names Genome Research Ltd and Wellcome Trust Sanger
 *    Institute nor the names of its contributors may be used to endorse
 *    or promote products derived from this software without specific
 *    prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY GENOME RESEARCH LTD AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GENOME RESEARCH
 * LTD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Author: James Bonfield, Wellcome Trust Sanger Institute. 2013
 */

/*! \file
 * SAM header parsing.
 *
 * These functions can be shared between SAM, BAM and CRAM file
 * formats as all three internally use the same string encoding for
 * header fields.
 *
 * Consider using the scram() generic API and calling
 * scram_get_header() to obtain the format-specific pointer to the
 * SAM_hdr struct.
 */ 

/*
 * TODO.
 *
 * - Sort order (parse to struct, enum type, updating funcs)
 * - Removal of lines.
 * - Updating of lines
 */

#ifndef _SAM_HDR_H_
#define _SAM_HDR_H_

#ifdef __cplusplus
extern "C" {
#endif

#include <stdarg.h>

#include "io_lib/dstring.h"
#include "io_lib/hash_table.h"
#include "io_lib/string_alloc.h"

/*
 * Proposed new SAM header parsing

1 @SQ ID:foo LN:100
2 @SQ ID:bar LN:200
3 @SQ ID:ram LN:300 UR:xyz
4 @RG ID:r ...
5 @RG ID:s ...

Hash table for 2-char keys without dup entries.
If dup lines, we form a circular linked list. Ie hash keys = {RG, SQ}.

HASH("SQ")--\
            |
    (3) <-> 1 <-> 2 <-> 3 <-> (1)

HASH("RG")--\
            |
    (5) <-> 4 <-> 5 <-> (4)

Items stored in the hash values also form their own linked lists:
Ie SQ->ID(foo)->LN(100)
   SQ->ID(bar)->LN(200)
   SQ->ID(ram)->LN(300)->UR(xyz)
   RG->ID(r)
 */

/*! A single key:value pair on a header line
 *
 * These form a linked list and hold strings. The strings are
 * allocated from a string_alloc_t pool refeenced in the master
 * SAM_hdr structure. Do not attempt to free, malloc or manipulate
 * these strings directly.
 */
typedef struct SAM_hdr_tag_s {
    struct SAM_hdr_tag_s *next;
    char *str;
    int   len;
} SAM_hdr_tag;

/*! The parsed version of the SAM header string.
 * 
 * Each header type (SQ, RG, HD, etc) points to its own SAM_hdr_type
 * struct via the main HashTable h in the SAM_hdr struct.
 *
 * These in turn consist of circular bi-directional linked lists (ie
 * rings) to hold the multiple instances of the same header type
 * code. For example if we have 5 \@SQ lines the primary hash table
 * will key on \@SQ pointing to the first SAM_hdr_type and that in turn
 * will be part of a ring of 5 elements.
 *
 * For each SAM_hdr_type structure we also point to a SAM_hdr_tag
 * structure which holds the tokenised attributes; the tab separated
 * key:value pairs per line.
 */
typedef struct SAM_hdr_item_s {
    struct SAM_hdr_item_s *next; // cirular
    struct SAM_hdr_item_s *prev;
    SAM_hdr_tag *tag;            // first tag
    int order;                   // 0 upwards
} SAM_hdr_type;

/*! Parsed \@SQ lines */
typedef struct {
    char *name;
    uint32_t len;
    SAM_hdr_type *ty;
    SAM_hdr_tag  *tag;
} SAM_SQ;

/*! Parsed \@RG lines */
typedef struct {
    char *name;
    SAM_hdr_type *ty;
    SAM_hdr_tag  *tag;
    int name_len;
    int id;           // numerical ID
} SAM_RG;

/*! Parsed \@PG lines */
typedef struct {
    char *name;
    SAM_hdr_type *ty;
    SAM_hdr_tag  *tag;
    int name_len;
    int id;           // numerical ID
    int prev_id;      // -1 if none
} SAM_PG;

/*! Sort order parsed from @HD line */
enum sam_sort_order {
    ORDER_UNKNOWN  =-1,
    ORDER_UNSORTED = 0,
    ORDER_NAME     = 1,
    ORDER_COORD    = 2,
  //ORDER_COLLATE  = 3 // maybe one day!
};

/*! Primary structure for header manipulation
 *
 * The initial header text is held in the text dstring_t, but is also
 * parsed out into SQ, RG and PG arrays. These have a HashTable
 * associated with each to allow lookup by ID or SN fields instead of
 * their numeric array indices. Additionally PG has an array to hold
 * the linked list start points (the last in a PP chain).
 *
 * Use the appropriate sam_hdr_* functions to edit the header, and 
 * call sam_hdr_rebuild() any time the textual form needs to be
 * updated again.
 */
typedef struct {
    dstring_t *text;          //!< concatenated text, indexed by SAM_hdr_tag
    HashTable *h;             //!< 2-char IDs, values are SAM_hdr_type
    string_alloc_t *str_pool; //!< Pool of SAM_hdr_tag->str strings
    pool_alloc_t   *type_pool;//!< Pool of SAM_hdr_type structs
    pool_alloc_t   *tag_pool; //!< Pool of SAM_hdr_tag structs

    // @SQ lines / references
    int nref;                 //!< Number of \@SQ lines
    SAM_SQ *ref;              //!< Array of parsed \@SQ lines
    HashTable *ref_hash;      //!< Hash table indexed by SN: field

    // @RG lines / read-groups
    int nrg;                  //!< Number of \@RG lines
    SAM_RG *rg;               //!< Array of parsed \@RG lines
    HashTable *rg_hash;	      //!< Hash table indexed by ID: field

    // @PG lines / programs
    int npg;                  //!< Number of \@PG lines
    int npg_end;              //!< Number of terminating \@PG lines
    int npg_end_alloc;        //!< Size of pg_end field
    SAM_PG *pg;		      //!< Array of parsed \@PG lines
    HashTable *pg_hash;	      //!< Hash table indexed by ID: field
    int *pg_end;              //!< \@PG chain termination IDs

    // @HD data
    enum sam_sort_order sort_order; //!< @HD SO: field

    // Order of first occurence of @?? lines.
    dstring_t *type_order;
    int ntypes;

    // @cond internal
    char ID_buf[1024];  // temporary buffer
    int ID_cnt;
    int ref_count;      // number of uses of this SAM_hdr
    // @endcond
} SAM_hdr;

/*! Creates an empty SAM header, ready to be populated.
 * 
 * @return
 * Returns a SAM_hdr struct on success (free with sam_hdr_free())
 *         NULL on failure
 */
SAM_hdr *sam_hdr_new();

/*! Tokenises a SAM header into a hash table.
 *
 * Also extracts a few bits on specific data types, such as @RG lines.
 *
 * @return
 * Returns a SAM_hdr struct on success (free with sam_hdr_free());
 *         NULL on failure
 */
#ifdef SAMTOOLS
SAM_hdr *sam_hdr_parse_(const char *hdr, int len);
#else
SAM_hdr *sam_hdr_parse(const char *hdr, int len);
#endif


/*! Produces a duplicate copy of hdr and returns it.
 * @return
 * Returns NULL on failure
 */
SAM_hdr *sam_hdr_dup(SAM_hdr *hdr);


/*! Increments a reference count on hdr.
 *
 * This permits multiple files to share the same header, all calling
 * sam_hdr_free when done, without causing errors for other open  files.
 */
void sam_hdr_incr_ref(SAM_hdr *hdr);


/*! Increments a reference count on hdr.
 *
 * This permits multiple files to share the same header, all calling
 * sam_hdr_free when done, without causing errors for other open  files.
 *
 * If the reference count hits zero then the header is automatically
 * freed. This makes it a synonym for sam_hdr_free().
 */
void sam_hdr_decr_ref(SAM_hdr *hdr);


/*! Deallocates all storage used by a SAM_hdr struct.
 *
 * This also decrements the header reference count. If after decrementing 
 * it is still non-zero then the header is assumed to be in use by another
 * caller and the free is not done.
 *
 * This is a synonym for sam_hdr_dec_ref().
 */
void sam_hdr_free(SAM_hdr *hdr);

/*! Returns the current length of the SAM_hdr in text form.
 *
 * Call sam_hdr_rebuild() first if editing has taken place.
 */
int sam_hdr_length(SAM_hdr *hdr);

/*! Returns the string form of the SAM_hdr.
 *
 * Call sam_hdr_rebuild() first if editing has taken place.
 */
char *sam_hdr_str(SAM_hdr *hdr);

/*! Appends a formatted line to an existing SAM header.
 *
 * Line is a full SAM header record, eg "@SQ\tSN:foo\tLN:100", with
 * optional new-line. If it contains more than 1 line then multiple lines
 * will be added in order.
 *
 * Input text is of maximum length len or as terminated earlier by a NUL.
 * Len may be 0 if unknown, in which case lines must be NUL-terminated.
 *
 * @return
 * Returns 0 on success;
 *        -1 on failure
 */
int sam_hdr_add_lines(SAM_hdr *sh, const char *lines, int len);

/*! Adds a single line to a SAM header.
 *
 * Specify type and one or more key,value pairs, ending with the NULL key.
 * Eg. sam_hdr_add(h, "SQ", "ID", "foo", "LN", "100", NULL).
 *
 * @return
 * Returns 0 on success;
 *        -1 on failure
 */
int sam_hdr_add(SAM_hdr *sh, const char *type, ...);

/*! Adds a single line to a SAM header.
 *
 * This is much like sam_hdr_add() but with the additional va_list
 * argument. This is followed by specifying type and one or more
 * key,value pairs, ending with the NULL key.
 *
 * Eg. sam_hdr_vadd(h, "SQ", args, "ID", "foo", "LN", "100", NULL).
 *
 * The purpose of the additional va_list parameter is to permit other
 * varargs functions to call this while including their own additional
 * parameters; an example is in sam_hdr_add_PG().
 *
 * @return
 * Returns 0 on success;
 *        -1 on failure
 */
int sam_hdr_vadd(SAM_hdr *sh, const char *type, va_list ap, ...);

/*!
 * @return
 * Returns the first header item matching 'type'. If ID is non-NULL it checks
 * for the tag ID: and compares against the specified ID.
 *
 * Returns NULL if no type/ID is found
 */
SAM_hdr_type *sam_hdr_find(SAM_hdr *hdr, char *type,
			   char *ID_key, char *ID_value);

/*!
 *
 * As per SAM_hdr_type, but returns a complete line of formatted text
 * for a specific head type/ID combination. If ID is NULL then it returns
 * the first line of the specified type.
 *
 * The returned string is malloced and should be freed by the calling
 * function with free().
 *
 * @return
 * Returns NULL if no type/ID is found.
 */
char *sam_hdr_find_line(SAM_hdr *hdr, char *type,
			char *ID_key, char *ID_value);

/*! Looks for a specific key in a single sam header line.
 *
 * If prev is non-NULL it also fills this out with the previous tag, to
 * permit use in key removal. *prev is set to NULL when the tag is the first
 * key in the list. When a tag isn't found, prev (if non NULL) will be the last
 * tag in the existing list.
 *
 * @return
 * Returns the tag pointer on success;
 *         NULL on failure
 */
SAM_hdr_tag *sam_hdr_find_key(SAM_hdr *sh,
			      SAM_hdr_type *type,
			      char *key,
			      SAM_hdr_tag **prev);

/*! Adds or updates tag key,value pairs in a header line.
 *
 * Eg for adding M5 tags to @SQ lines or updating sort order for the
 * @HD line (although use the sam_hdr_sort_order() function for
 * HD manipulation, which is a wrapper around this funuction).
 *
 * Specify multiple key,value pairs ending in NULL.
 *
 * @return
 * Returns 0 on success;
 *        -1 on failure
 */
int sam_hdr_update(SAM_hdr *hdr, SAM_hdr_type *type, ...);

/*! Returns the sort order from the @HD SO: field */
enum sam_sort_order sam_hdr_sort_order(SAM_hdr *hdr);

/*! Reconstructs the dstring from the header hash table.
 * @return
 * Returns 0 on success;
 *        -1 on failure
 */
int sam_hdr_rebuild(SAM_hdr *hdr);

/*! Looks up a reference sequence by name and returns the numerical ID.
 * @return
 * Returns -1 if unknown reference.
 */
int sam_hdr_name2ref(SAM_hdr *hdr, char *ref);

/*! Looks up a read-group by name and returns a pointer to the start of the
 * associated tag list.
 *
 * @return
 * Returns NULL on failure
 */
SAM_RG *sam_hdr_find_rg(SAM_hdr *hdr, char *rg);

/*! Fixes any PP links in @PG headers.
 *
 * If the entries are in order then this doesn't need doing, but incase
 * our header is out of order this goes through the sh->pg[] array
 * setting the prev_id field.
 *
 * @return
 * Returns 0 on sucess;
 *        -1 on failure (indicating broken PG/PP records)
 */
int sam_hdr_link_pg(SAM_hdr *hdr);


/*! Add an @PG line.
 *
 * If we wish complete control over this use sam_hdr_add() directly. This
 * function uses that, but attempts to do a lot of tedious house work for
 * you too.
 *
 * - It will generate a suitable ID if the supplied one clashes.
 * - It will generate multiple @PG records if we have multiple PG chains.
 *
 * Call it as per sam_hdr_add() with a series of key,value pairs ending
 * in NULL.
 *
 * @return
 * Returns 0 on success;
 *        -1 on failure
 */
int sam_hdr_add_PG(SAM_hdr *sh, const char *name, ...);

/*!
 * A function to help with construction of CL tags in @PG records.
 * Takes an argc, argv pair and returns a single space-separated string.
 * This string should be deallocated by the calling function.
 * 
 * @return
 * Returns malloced char * on success;
 *         NULL on failure
 */
char *stringify_argv(int argc, char *argv[]);

#ifdef __cplusplus
}
#endif

#endif /* _SAM_HDR_H_ */