#include "cst_agent.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MODEL_MAX_LEN 128

static const cst_provider_t PROVIDERS[] = {
    {"minimax", "https://api.minimax.cn/v1", "MiniMax-M2.7", "MINIMAX_API_KEY"},
    {"deepseek", "https://api.deepseek.com/v1", "deepseek-flash",
     "DEEPSEEK_API_KEY"},
    {"openai", "https://api.openai.com/v1", "gpt-4.1-mini", "OPENAI_API_KEY"},
};

const cst_provider_t *cst_provider_find(const char *name) {
  if (!name || !name[0])
    return NULL;
  for (size_t i = 0; i < sizeof(PROVIDERS) / sizeof(PROVIDERS[0]); i++) {
    if (strcmp(PROVIDERS[i].name, name) == 0)
      return &PROVIDERS[i];
  }
  return NULL;
}

const cst_provider_t *cst_provider_default(void) {
  const cst_provider_t *p = cst_provider_find(getenv("CST_PROVIDER"));
  return p ? p : &PROVIDERS[0];
}

static int already(char out[][MODEL_MAX_LEN], int n, const char *name) {
  for (int i = 0; i < n; i++) {
    if (strcmp(out[i], name) == 0)
      return 1;
  }
  return 0;
}

static int push(char out[][MODEL_MAX_LEN], int *n, int max, const char *name) {
  if (!name || !name[0] || *n >= max)
    return 0;
  if (already(out, *n, name))
    return 0;
  snprintf(out[*n], MODEL_MAX_LEN, "%s", name);
  (*n)++;
  return 1;
}

int cst_models_list(const char *current, char out[][128], int max_out) {
  if (!out || max_out <= 0)
    return 0;
  int n = 0;

  const char *env = getenv("CST_MODELS");
  if (env && env[0]) {
    char buf[1024];
    snprintf(buf, sizeof(buf), "%s", env);
    char *p = buf;
    while (*p && n < max_out) {
      while (*p == ':' || *p == ' ' || *p == ',')
        p++;
      if (!*p)
        break;
      char *start = p;
      while (*p && *p != ':' && *p != ',')
        p++;
      char save = *p;
      *p = 0;
      char *end = start + strlen(start);
      while (end > start && (end[-1] == ' ' || end[-1] == '\t'))
        *--end = 0;
      push(out, &n, max_out, start);
      *p = save;
      if (*p)
        p++;
    }
  } else {
    push(out, &n, max_out, "deepseek-flash");
    push(out, &n, max_out, "deepseek-v4-pro");
    push(out, &n, max_out, "MiniMax-M2.7");
    push(out, &n, max_out, "MiniMax-M2.5");
    push(out, &n, max_out, "gpt-4.1-mini");
    push(out, &n, max_out, "gpt-4o");
  }

  if (current && current[0])
    push(out, &n, max_out, current);

  return n;
}

/* Context window in tokens (CST_CTX_TOKENS overrides). Prefix match. */
long cst_model_context_tokens(const char *model) {
  const char *e = getenv("CST_CTX_TOKENS");
  if (e && atol(e) > 0)
    return atol(e);
  static const struct {
    const char *prefix;
    long tokens;
  } T[] = {{"deepseek", 128000}, {"MiniMax", 196608}, {"minimax", 196608},
           {"gpt-4.1", 1047576}, {"gpt-4o", 128000},  {"gpt-5", 400000},
           {"o3", 200000},       {"o4", 200000},      {"claude", 200000},
           {"qwen", 131072},     {"glm", 128000},     {"kimi", 131072}};
  if (model) {
    for (size_t i = 0; i < sizeof(T) / sizeof(T[0]); i++) {
      if (strncmp(model, T[i].prefix, strlen(T[i].prefix)) == 0)
        return T[i].tokens;
    }
  }
  return 128000;
}

int cst_effort_valid(const char *effort) {
  static const char *const ok[] = {"low", "medium", "high", "max"};
  for (size_t i = 0; effort && i < sizeof(ok) / sizeof(ok[0]); i++) {
    if (strcmp(effort, ok[i]) == 0)
      return 1;
  }
  return 0;
}

const char *cst_effort_wire(const char *provider, const char *model,
                            const char *effort) {
  if (!cst_effort_valid(effort) || !provider || !model)
    return NULL;
  if (strcmp(provider, "deepseek") == 0)
    return effort;
  /* OpenAI reasoning models take low | medium | high. */
  if (strcmp(provider, "openai") == 0 &&
      (strncmp(model, "o1", 2) == 0 || strncmp(model, "o3", 2) == 0 ||
       strncmp(model, "o4", 2) == 0 || strncmp(model, "gpt-5", 5) == 0))
    return strcmp(effort, "max") == 0 ? "high" : effort;
  return NULL;
}

int cst_provider_count(void) {
  return (int)(sizeof(PROVIDERS) / sizeof(PROVIDERS[0]));
}

const cst_provider_t *cst_provider_at(int i) {
  return i >= 0 && i < cst_provider_count() ? &PROVIDERS[i] : NULL;
}