use crate::keywords::{is_function_start, is_procedure_start};
use crate::models::{ParsedCall, SourceRange};
use crate::parser::{extract_name_from_header, routine_ended};

pub fn extract_calls(source: &str) -> Vec<ParsedCall> {
    let mut result = Vec::new();
    let mut current_routine: Option<String> = None;
    for (index, line) in source.lines().enumerate() {
        let line_no = index + 1;
        let trimmed = strip_inline_comment(line).trim();
        if is_procedure_start(trimmed) || is_function_start(trimmed) {
            current_routine = Some(extract_name_from_header(trimmed));
            continue;
        }
        if routine_ended(trimmed) {
            current_routine = None;
            continue;
        }
        let Some(caller) = current_routine.as_ref() else {
            continue;
        };
        if let Some(callee) = simple_call_name(trimmed).or_else(|| condition_call_name(trimmed)) {
            result.push(ParsedCall {
                caller: caller.clone(),
                callee,
                source_range: SourceRange {
                    line_start: line_no,
                    line_end: line_no,
                    column_start: 1,
                    column_end: line.len() + 1,
                },
            });
        }
    }
    result
}

fn simple_call_name(line: &str) -> Option<String> {
    if !line.ends_with(';') || !line.contains('(') || !line.contains(')') || line.contains('.') {
        return None;
    }
    let call_expr = line.split('=').next_back().unwrap_or(line).trim();
    let name = call_expr.split('(').next()?.trim();
    if name.is_empty() {
        return None;
    }
    Some(name.to_string())
}

fn condition_call_name(line: &str) -> Option<String> {
    let lowered = line.to_lowercase();
    let is_condition = (lowered.starts_with("если ") && lowered.contains(" тогда"))
        || (lowered.starts_with("if ") && lowered.contains(" then"));
    if !is_condition || line.contains('.') {
        return None;
    }
    let before_then = if let Some(index) = lowered.find(" тогда") {
        &line[..index]
    } else if let Some(index) = lowered.find(" then") {
        &line[..index]
    } else {
        line
    };
    let name_part = before_then.split('(').next()?.split_whitespace().last()?;
    if name_part.eq_ignore_ascii_case("Если") || name_part.eq_ignore_ascii_case("If") {
        return None;
    }
    Some(name_part.to_string())
}

fn strip_inline_comment(line: &str) -> &str {
    line.split("//").next().unwrap_or(line)
}