#ifndef SCANNER_H
#define SCANNER_H

#include "types.h"

/* Token kinds. */
typedef enum {
    /* End of file token generated by the scanner
     * when the input is exhausted. */
    T_EOF,

    /* Special "error" token. */
    T_INVALID,

    /* Single-char tokens. */
    T_LPAREN,     /* ( */
    T_RPAREN,     /* ) */
    T_LBRACE,     /* { */
    T_RBRACE,     /* } */
    T_LBRACKET,   /* [ */
    T_RBRACKET,   /* ] */
    T_COMMA,      /* , */
    T_DOT,        /* . */
    T_DOT_DOT,    /* .. */
    T_MINUS,      /* - */
    T_PLUS,       /* + */
    T_SEMICOLON,  /* ; */
    T_SLASH,      /* / */
    T_STAR,       /* * */
    T_PERCENT,    /* % */
    T_AMP,        /* & */
    T_PIPE,       /* | */
    T_CARET,      /* ^ */
    T_TILDE,      /* ~ */
    T_UNDERSCORE, /* _ */

    /* One or two char tokens. */
    T_QUESTION, /* ? */
    T_BANG,     /* ! */
    T_BANG_EQ,  /* != */
    T_EQ,       /* = */
    T_EQ_EQ,    /* == */
    T_GT,       /* > */
    T_GT_EQ,    /* >= */
    T_LT,       /* < */
    T_LT_EQ,    /* <= */
    T_LSHIFT,   /* << */
    T_RSHIFT,   /* >> */

    /* Literals. */
    T_IDENT,    /* fnord */
    T_AT_IDENT, /* @sizeOf */
    T_STRING,   /* "fnord" */
    T_CHAR,     /* 'f' */
    T_NUMBER,   /* 42 */
    T_TRUE,     /* true */
    T_FALSE,    /* false */
    T_NIL,      /* nil */
    T_UNDEF,    /* undefined */

    /* Keywords. */
    T_IF,
    T_ELSE,
    T_RETURN,
    T_BREAK,
    T_CONTINUE,
    T_THROW,
    T_PANIC,
    T_WHILE,
    T_FOR,
    T_LOOP,
    T_TRY,
    T_CATCH,
    T_IN,
    T_FN,
    T_UNION,
    T_RECORD,
    T_DEFAULT,
    T_PUB,
    T_MUT,
    T_CONST,
    T_STATIC,
    T_LET,
    T_AND,
    T_OR,
    T_NOT,
    T_MATCH,
    T_CASE,
    T_USE,
    T_SUPER,  /* super */
    T_EXTERN, /* extern */
    T_MOD,    /* mod */
    T_AS,     /* as */
    T_ALIGN,  /* align */
    T_THROWS, /* throws */

    /* Type-related tokens. */
    T_COLON,       /* : */
    T_COLON_COLON, /* :: */
    T_ARROW,       /* -> */
    T_FAT_ARROW,   /* => */

    /* Builtin type names. */
    T_I8,
    T_I16,
    T_I32,
    T_I64,
    T_U8,
    T_U16,
    T_U32,
    T_U64,
    T_F32,
    T_BOOL,
    T_VOID,
    T_OPAQUE
} tokenclass_t;

/* Code location. */
typedef struct {
    const char *src;  /* Pointer to source code location. */
    const char *file; /* File path. */
    u32         line; /* line number. */
    u32         col;  /* Column number. */
} location_t;

/* Token structure. */
typedef struct {
    tokenclass_t cls;
    const char  *start;    /* Start of the token in the source code. */
    u32          length;   /* Byte length of token in source code. */
    u32          position; /* Byte offset in source. */
} token_t;

/* Scanner state. */
typedef struct {
    const char *file;   /* File path. */
    const char *source; /* Start of source buffer. */
    const char *token;  /* Start of current token. */
    const char *cursor; /* Current position. */
} scanner_t;

/* Initialize scanner with source text. */
void scanner_init(scanner_t *s, const char *file, const char *source);

/* Get next token from scanner. */
token_t scanner_next(scanner_t *s);

/* Get line and column information for a token. */
location_t scanner_get_location(scanner_t *s, u32 position);

#endif