#ifndef SIX_L_H
#define SIX_L_H

#include <stddef.h>
#include <stdint.h>
#include <stdio.h>

typedef int8_t   i8;
typedef int16_t  i16;
typedef int32_t  i32;
typedef int64_t  i64;
typedef uint8_t  u8;
typedef uint16_t u16;
typedef uint32_t u32;
typedef uint64_t u64;

typedef struct Lsym  Lsym;
typedef struct Lrel  Lrel;
typedef struct Lobj  Lobj;
typedef struct Lso   Lso;
typedef struct Lnk   Lnk;

struct Lsym {
	const char *name;
	u64	val;		/* offset within combined .text (or .data when
				 * in_data=1) once linked */
	int	defined;	/* 1 if a Lobj defines this symbol */
	int	in_data;	/* 1 if defined in .data (writable globals);
				 * 0 means .text (the default). Mutually
				 * exclusive with is_dyn. */
	Lobj	*owner;
	int	idx_in_owner;
	/* Dynamic-linking fields. Set by l_resolve when an undefined sym
	 * is provided by some loaded Lso. Patched-in PLT slot index lets
	 * the relocator route PC32/PLT32 references through the stub. */
	int	is_dyn;
	Lso	*dyn_lib;
	const char *dyn_version;	/* matched export's version, NULL if none */
	int	plt_idx;	/* 0..dyn_n-1, -1 if no PLT slot */
	int	dynsym_idx;	/* index in emitted .dynsym, -1 otherwise */
	Lsym	*next;
};

struct Lrel {
	u64	off;		/* offset within the relocation's section */
	int	section;	/* 0 = .text, 1 = .data */
	int	kind;		/* R_X86_64_* */
	Lsym	*sym;
	i64	addend;
	Lrel	*next;
};

struct Lobj {
	const char *path;
	u8	*buf;		/* mmapped or read-in object bytes */
	u64	len;
	u64	text_off;	/* offset of .text in combined output */
	u64	text_size;
	u64	data_off;	/* offset of .data in combined output */
	u64	data_size;	/* bytes contributed to combined .data (0 if none) */
	Lobj	*next;
};

struct Lso {
	const char *path;	/* full filesystem path used to load */
	const char *soname;	/* DT_SONAME, or basename if missing */
	char	**exports;	/* NULL-terminated list of GLOBAL/WEAK syms */
	char	**versions;	/* parallel to exports[]; NULL for unversioned,
				 * else strdup'd version name e.g. "GLIBC_2.2.5" */
	Lso	*next;
};

struct Lnk {
	Lobj	*objs;
	Lso	*sos;
	Lsym	*syms;
	Lrel	*rels;
	u8	*text;		/* combined .text */
	u64	textcap, textlen;
	u8	*data;		/* combined .data (writable). Empty unless any
				 * input .o has a .data PROGBITS section. */
	u64	datacap, datalen;
	int	errs;
	int	dyn_n;		/* number of symbols routed through PLT */
};

/* obj.c */
int	l_load(Lnk*, const char *path);
int	l_read_all(const char *path, u8 **out, u64 *len);	/* shared helper */
/* dyn.c */
int	l_load_so(Lnk*, const char *path);
int	l_so_provides(Lso*, const char *name);
/* l_so_provides_v: same, but also returns the export's version name
 * (NULL for unversioned globals) via *out_version on a hit. */
int	l_so_provides_v(Lso*, const char *name, const char **out_version);
/* sym.c */
Lsym	*l_intern(Lnk*, const char *name);
Lsym	*l_lookup(Lnk*, const char *name);
/* pass.c */
int	l_resolve(Lnk*);
/* Patch relocations in l->text. text_va is the VA where .text will be
 * mapped; data_va is the VA where .data will be mapped (pass 0 if no
 * data symbols). PC32/PLT32 displacements between text symbols cancel
 * the absolute VA, but data targets need the real data_va. */
int	l_relocate(Lnk*, u64 text_va, u64 data_va);
/* out.c */
int	l_emit_elf(Lnk*, FILE *out, u64 base, u64 entry);
/* dynout.c — emit a dynamic-linked ELF executable. Called by
 * l_emit_elf when l->sos is non-empty. */
int	l_emit_dyn_elf(Lnk*, FILE *out, u64 base, u64 entry);

#endif