#!/bin/bash
# Prompt assembly — composes the final prompt from base + mode overlay.
# Injects runtime variables (scope budgets, current story, iteration count).

# Build the complete prompt for a given agent role and mode.
# Usage: build_prompt "generator" "implement"
#        build_prompt "evaluator" "implement"
build_prompt() {
    local role="$1"    # generator | evaluator
    local mode="$2"    # implement | explore | fix

    local base_file="$LOOP_DIR/prompts/${role}/_base.md"
    local mode_file="$LOOP_DIR/prompts/${role}/${mode}.md"

    local prompt=""

    # Start with base prompt
    if [ -f "$base_file" ]; then
        prompt=$(cat "$base_file")
    else
        log "WARNING: Missing base prompt: $base_file"
        return 1
    fi

    # Append mode-specific overlay
    if [ -f "$mode_file" ]; then
        prompt="${prompt}

---

$(cat "$mode_file")"
    else
        log "WARNING: Missing mode prompt: $mode_file"
    fi

    # Inject runtime variables
    prompt=$(inject_variables "$prompt" "$mode")

    printf '%s\n' "$prompt"
}

# Replace template variables in prompt text
inject_variables() {
    local text="$1"
    local mode="$2"

    # Scope budgets from config
    local max_read max_write max_modify
    max_read=$(get_config_value ".scopeBudgets.${mode}.maxFilesToRead" "50")
    max_write=$(get_config_value ".scopeBudgets.${mode}.maxLinesToWrite" "500")
    max_modify=$(get_config_value ".scopeBudgets.${mode}.maxFilesToModify" "10")

    text="${text//\{\{MAX_FILES_TO_READ\}\}/$max_read}"
    text="${text//\{\{MAX_LINES_TO_WRITE\}\}/$max_write}"
    text="${text//\{\{MAX_FILES_TO_MODIFY\}\}/$max_modify}"
    text="${text//\{\{MODE\}\}/$mode}"
    text="${text//\{\{ITERATION\}\}/$ITERATION}"
    text="${text//\{\{MAX_ITERATIONS\}\}/$MAX_ITERATIONS}"
    text="${text//\{\{LOOP_DIR\}\}/$LOOP_DIR}"
    text="${text//\{\{PROJECT_ROOT\}\}/$PROJECT_ROOT}"
    text="${text//\{\{CURRENT_STORY_ID\}\}/${CURRENT_STORY_ID:-unknown}}"
    text="${text//\{\{PRE_GENERATOR_SHA\}\}/${PRE_GENERATOR_SHA:-HEAD~1}}"

    printf '%s\n' "$text"
}

# Read a value from config.json with a default fallback
get_config_value() {
    local path="$1"
    local default="$2"
    local config="$LOOP_DIR/config.json"

    [ -f "$config" ] || { echo "$default"; return; }

    if command -v jq &>/dev/null; then
        local val
        val=$(jq -r "$path // empty" "$config" 2>/dev/null)
        echo "${val:-$default}"
    else
        LOOP_CONFIG="$config" LOOP_PATH="$path" LOOP_DEFAULT="$default" python3 -c "
import json, os
d = json.load(open(os.environ['LOOP_CONFIG']))
keys = os.environ['LOOP_PATH'].lstrip('.').split('.')
for k in keys:
    d = d.get(k) if isinstance(d, dict) else None
    if d is None:
        break
val = d if d is not None and d != {} else os.environ['LOOP_DEFAULT']
# Normalize Python booleans to lowercase for shell compatibility
if isinstance(val, bool):
    val = str(val).lower()
print(val, end='')
"
    fi
}