#' @tool_code ST_META_ANALYSIS
#' @name Meta 分析引擎
#' @version 1.0.0
#' @description 支持 HR/二分类/连续型三种数据类型的 Meta 分析，生成森林图和漏斗图
#' @author ASL Evidence Synthesis Team

library(glue)
library(ggplot2)
library(base64enc)

run_analysis <- function(input) {
  logs <- c()
  log_add <- function(msg) { logs <<- c(logs, paste0("[", Sys.time(), "] ", msg)) }
  warnings_list <- c()

  # ===== 依赖检查 =====
  if (!requireNamespace("meta", quietly = TRUE)) {
    return(make_error(ERROR_CODES$E101_PACKAGE_MISSING, package = "meta"))
  }
  library(meta)

  # ===== 数据加载 =====
  log_add("Loading input data")
  df <- tryCatch(
    load_input_data(input),
    error = function(e) {
      log_add(paste("Data loading failed:", e$message))
      return(NULL)
    }
  )

  if (is.null(df) || nrow(df) < 2) {
    return(make_error(ERROR_CODES$E004_SAMPLE_TOO_SMALL, n = ifelse(is.null(df), 0, nrow(df)), min_required = 2))
  }
  log_add(glue("Data loaded: {nrow(df)} studies, {ncol(df)} columns"))

  # ===== 参数提取 =====
  p <- input$params
  data_type <- tolower(p$data_type %||% "hr")
  model_type <- tolower(p$model %||% "random")
  effect_measure <- toupper(p$effect_measure %||% "")

  use_random <- model_type == "random"
  use_fixed  <- model_type == "fixed"

  log_add(glue("Config: data_type={data_type}, model={model_type}"))

  # ===== 执行 Meta 分析 =====
  ma_result <- NULL

  ma_result <- tryCatch(
    withCallingHandlers(
      {
        if (data_type == "hr") {
          run_hr_meta(df, use_random, use_fixed, log_add)
        } else if (data_type == "dichotomous") {
          sm <- if (effect_measure %in% c("OR", "RR", "RD")) effect_measure else "OR"
          run_dichotomous_meta(df, sm, use_random, use_fixed, log_add)
        } else if (data_type == "continuous") {
          run_continuous_meta(df, use_random, use_fixed, log_add)
        } else {
          return(make_error(ERROR_CODES$E100_INTERNAL_ERROR, details = glue("Unknown data_type: {data_type}")))
        }
      },
      warning = function(w) {
        warnings_list <<- c(warnings_list, w$message)
        invokeRestart("muffleWarning")
      }
    ),
    error = function(e) {
      log_add(glue("Meta-analysis failed: {e$message}"))
      return(NULL)
    }
  )

  if (is.null(ma_result)) {
    return(list(
      status = "error",
      error_code = "E100",
      message = "Meta-analysis computation failed. Check data format.",
      user_hint = "Please verify your data columns and values.",
      trace_log = logs
    ))
  }

  # ===== 提取结果 =====
  log_add("Extracting results")

  is_random <- use_random
  pooled_te <- if (is_random) ma_result$TE.random else ma_result$TE.fixed
  pooled_lower <- if (is_random) ma_result$lower.random else ma_result$lower.fixed
  pooled_upper <- if (is_random) ma_result$upper.random else ma_result$upper.fixed
  pooled_pval <- if (is_random) ma_result$pval.random else ma_result$pval.fixed

  i2_val <- ma_result$I2
  tau2_val <- if (!is.null(ma_result$tau2)) ma_result$tau2 else NA
  q_stat <- ma_result$Q
  q_pval <- ma_result$pval.Q
  k_studies <- ma_result$k

  sm_label <- ma_result$sm

  # Back-transform ratio measures from log scale (HR, OR, RR)
  is_ratio <- sm_label %in% c("HR", "OR", "RR")
  display_te    <- if (is_ratio) exp(pooled_te) else pooled_te
  display_lower <- if (is_ratio) exp(pooled_lower) else pooled_lower
  display_upper <- if (is_ratio) exp(pooled_upper) else pooled_upper

  log_add(glue("Back-transform: is_ratio={is_ratio}, raw_TE={round(pooled_te,4)}, display={round(display_te,4)}"))

  results_list <- list(
    pooled_effect = jsonlite::unbox(round(display_te, 4)),
    pooled_lower  = jsonlite::unbox(round(display_lower, 4)),
    pooled_upper  = jsonlite::unbox(round(display_upper, 4)),
    pooled_pvalue = jsonlite::unbox(round(pooled_pval, 6)),
    i_squared     = jsonlite::unbox(round(i2_val * 100, 1)),
    tau_squared   = jsonlite::unbox(round(tau2_val, 4)),
    q_statistic   = jsonlite::unbox(round(q_stat, 2)),
    q_pvalue      = jsonlite::unbox(round(q_pval, 6)),
    k_studies     = jsonlite::unbox(k_studies),
    effect_measure = jsonlite::unbox(sm_label),
    model          = jsonlite::unbox(ifelse(is_random, "Random Effects", "Fixed Effect"))
  )

  # ===== 生成图表 =====
  log_add("Generating forest plot")
  forest_b64 <- generate_forest_plot(ma_result)

  log_add("Generating funnel plot")
  funnel_b64 <- generate_funnel_plot(ma_result)

  # ===== 构建 report_blocks =====
  blocks <- list()

  kv_items <- list()
  kv_items[["Effect Measure"]] <- sm_label
  kv_items[["Model"]] <- ifelse(is_random, "Random Effects (DerSimonian-Laird)", "Fixed Effect (Mantel-Haenszel)")
  kv_items[["Studies (k)"]] <- as.character(k_studies)
  kv_items[["Pooled Effect"]] <- glue("{round(display_te, 3)} [{round(display_lower, 3)}, {round(display_upper, 3)}]")
  kv_items[["P-value"]] <- format_p_value(pooled_pval)
  kv_items[["I\u00b2 (heterogeneity)"]] <- glue("{round(i2_val * 100, 1)}%")
  kv_items[["Q statistic"]] <- glue("{round(q_stat, 2)} (p = {format_p_value(q_pval)})")

  blocks[[length(blocks) + 1]] <- make_kv_block(kv_items, title = "Meta-Analysis Summary")

  if (!is.null(forest_b64)) {
    blocks[[length(blocks) + 1]] <- make_image_block(forest_b64, title = "Forest Plot", alt = "Forest plot of meta-analysis")
  }
  if (!is.null(funnel_b64)) {
    blocks[[length(blocks) + 1]] <- make_image_block(funnel_b64, title = "Funnel Plot", alt = "Funnel plot for publication bias assessment")
  }

  heterogeneity_text <- if (i2_val * 100 > 75) {
    glue("Substantial heterogeneity observed (I\u00b2 = {round(i2_val*100,1)}%). Consider subgroup analysis or meta-regression.")
  } else if (i2_val * 100 > 50) {
    glue("Moderate heterogeneity (I\u00b2 = {round(i2_val*100,1)}%). Results should be interpreted with caution.")
  } else {
    glue("Low heterogeneity (I\u00b2 = {round(i2_val*100,1)}%). Studies appear reasonably homogeneous.")
  }
  blocks[[length(blocks) + 1]] <- make_markdown_block(heterogeneity_text, title = "Heterogeneity Assessment")

  # ===== 可复现代码 =====
  reproducible_code <- glue('
# Auto-generated by AI Clinical Research Platform
# Tool: Meta-Analysis Engine (ST_META_ANALYSIS)
# Time: {Sys.time()}
# ================================

library(meta)

# Your data:
# df <- read.csv("meta_data.csv")

# Run meta-analysis:
# ma <- metagen(TE = log(df$hr), seTE = ..., studlab = df$study_id, sm = "{sm_label}")
# forest(ma)
# funnel(ma)
')

  plots_list <- list()
  if (!is.null(forest_b64)) plots_list[[length(plots_list) + 1]] <- forest_b64
  if (!is.null(funnel_b64)) plots_list[[length(plots_list) + 1]] <- funnel_b64

  log_add("Analysis complete")

  return(list(
    status = "success",
    message = glue("Meta-analysis completed: {k_studies} studies, model={model_type}"),
    warnings = if (length(warnings_list) > 0) warnings_list else NULL,
    results = results_list,
    report_blocks = blocks,
    plots = plots_list,
    trace_log = logs,
    reproducible_code = as.character(reproducible_code)
  ))
}

# ===== Sub-functions =====

`%||%` <- function(a, b) if (is.null(a)) b else a

format_p_value <- function(p) {
  if (is.na(p)) return("NA")
  if (p < 0.001) return("p < .001")
  return(paste0("p = ", formatC(p, format = "f", digits = 3)))
}

run_hr_meta <- function(df, use_random, use_fixed, log_add) {
  required <- c("hr", "lower_ci", "upper_ci")
  check_columns(df, required)

  studlab <- if ("study_id" %in% names(df)) as.character(df$study_id) else paste0("Study ", seq_len(nrow(df)))

  te <- log(df$hr)
  se <- (log(df$upper_ci) - log(df$lower_ci)) / (2 * qnorm(0.975))

  log_add(glue("Running metagen() with {length(te)} studies, sm=HR"))

  metagen(
    TE = te, seTE = se, studlab = studlab,
    sm = "HR", method.tau = "DL",
    random = use_random, fixed = use_fixed
  )
}

run_dichotomous_meta <- function(df, sm, use_random, use_fixed, log_add) {
  required <- c("events_e", "total_e", "events_c", "total_c")
  check_columns(df, required)

  studlab <- if ("study_id" %in% names(df)) as.character(df$study_id) else paste0("Study ", seq_len(nrow(df)))

  log_add(glue("Running metabin() with {nrow(df)} studies, sm={sm}"))

  metabin(
    event.e = df$events_e, n.e = df$total_e,
    event.c = df$events_c, n.c = df$total_c,
    studlab = studlab, sm = sm, method.tau = "DL",
    random = use_random, fixed = use_fixed
  )
}

run_continuous_meta <- function(df, use_random, use_fixed, log_add) {
  required <- c("mean_e", "sd_e", "n_e", "mean_c", "sd_c", "n_c")
  check_columns(df, required)

  studlab <- if ("study_id" %in% names(df)) as.character(df$study_id) else paste0("Study ", seq_len(nrow(df)))

  log_add(glue("Running metacont() with {nrow(df)} studies, sm=MD"))

  metacont(
    n.e = df$n_e, mean.e = df$mean_e, sd.e = df$sd_e,
    n.c = df$n_c, mean.c = df$mean_c, sd.c = df$sd_c,
    studlab = studlab, sm = "MD", method.tau = "DL",
    random = use_random, fixed = use_fixed
  )
}

check_columns <- function(df, required) {
  missing <- required[!(required %in% names(df))]
  if (length(missing) > 0) {
    stop(glue("Missing required columns: {paste(missing, collapse=', ')}"))
  }
}

generate_forest_plot <- function(ma) {
  tryCatch({
    plot_h <- max(400, 120 + ma$k * 35)
    tmp <- tempfile(fileext = ".png")
    png(tmp, width = 900, height = plot_h, res = 100)
    meta::forest(ma, sortvar = ma$TE, print.tau2 = TRUE, print.I2 = TRUE,
                 col.diamond = "steelblue", col.square = "royalblue")
    dev.off()
    b64 <- base64encode(tmp)
    unlink(tmp)
    paste0("data:image/png;base64,", b64)
  }, error = function(e) {
    message(glue("[META] Forest plot error: {e$message}"))
    NULL
  })
}

generate_funnel_plot <- function(ma) {
  tryCatch({
    tmp <- tempfile(fileext = ".png")
    png(tmp, width = 600, height = 500, res = 100)
    meta::funnel(ma, studlab = TRUE, cex.studlab = 0.8)
    dev.off()
    b64 <- base64encode(tmp)
    unlink(tmp)
    paste0("data:image/png;base64,", b64)
  }, error = function(e) {
    message(glue("[META] Funnel plot error: {e$message}"))
    NULL
  })
}